Question

In N type semiconductor the fermi level lies 0.3 eV below the conduction band at 300 K, if the temperature is to 330 K, determine the new position of the fermi level.

Answer 1

Explanation:

When the temperature of a semiconductor is raised to KT, the position of Fermi level is raised by KT (kT is the amount of heat required to increase the thermodynamic entropy of a system by k) from its initial position at a given temperature, where ‘K’ is Boltzmann constant

  (K = 1.38× 10−23JK−1).

Also, 

Eg(energy band gap) ∝   1/T

Eg/E'g=T'/T

0.3/E'g=330/300

E'g=300×0.3/330

=0.27eV

0.27 eV below the conduction band.